How Air-Conditioners Work: What You Need To Know


They are magical boxes that emit cold air when plugged into a power source which also allows you to control the temperature of the air that is blown out of it -- how amazing is that? Most homes in Singapore have at least one air-conditioner unit installed to alleviate the discomfort caused by the blazing sun during the hotter months and we are all familiar with how to operate them. Have you ever wondered what happens inside of a unit and how it all works together to give us marvellously cooled rooms? Read on and learn more about how air-conditioners work!

The main function of an air-conditioner is to transfer the hot air from inside a room outside into the atmospheric air. Regardless of which type of system it is, all air-conditioner consists of 5 parts: refrigerant, condenser, compressor, expansion valve and evaporator coil.



The refrigerant is the chemical that helps cool the air. How it works is that as heat from inside the room is collected by the air-conditioner, the refrigerant changes from a gaseous state to a liquid state in order to facilitate the transfer of the heat from inside the house out.

Refrigerant is the key to keeping air-conditioners working properly without having to reach high levels of heat as it is able to change states at a low temperature because of its extremely low boiling point.



The compressor aids in converting the refrigerant from a gaseous state to a hot liquid state through pressurization as it passes through it. From the compressor, refrigerant is then transferred out into the condenser as a high temperature vapor.



As it name suggest, the condenser is a device that is used to condense chemicals from its gaseous to liquid state by means of lowering its temperature. There is a condenser fan inside the condenser that blows air over condensing coils to cool the refrigerant that is pumped through here. The refrigerant then changes from hot vapor to hot liquid before being pumped to the next air-conditioner part.


Expansion Valve

This is the part that does all the heavy lifting in the air-conditioning system – the expansion valve. What happens when the refrigerant, which is in a hot liquid state at this point as it exits the condenser, arrives at the expansion valve is that it will enter through a tiny opening on one end and come out of the expansion valve as a cool, low temperature gas. This works on the natural process of gas as the expansion valve depressurizes the hot liquid refrigerant, allowing it to expand and change into a cool gaseous state.


Evaporator Coil

Before cool air is blown into your room, it has to first go through the evaporator coil of the air-conditioner. Evaporator coils are usually made of copper, aluminum or steel which are all good conductors of heat and are located near the blower fan of the unit. As the refrigerant flows to the area where the evaporator coil is, the blower fan blows hot air from the room onto the evaporator coil where the cooled refrigerant will lower its temperature and have it pushed out the unit back into the room.